Summit Therapeutics SMMT Insider Ownership

NASDAQ SMMT

$15.55 -0.28 (-1.77%)

At close: Oct 22, 2026 · 4:00 PM EDT

Insider Holdings by Owner

1.21Bn Shares

Insider Ownership Statistics

as of 30 Sep, 2026

Insider Ownership

81.37%

■0% pp QoQ

Shares Held by Insiders

645.40Mn

filed for Sep 2026

■0.00% QoQ

Shares Outstanding

793.12Mn

793,120,362 shares

Direct Holdings

577.20Mn

Indirect: 68.20Mn

Net Shares Traded (QoQ)

no net change in Sep 2026

Insiders Holding Shares

with Form 4 holdings on file

Shares Owned by Insiders

Shares held % of outstanding

Latest —

Average ownership —

Peak ownership —

Shares Purchased/Sold by Insiders

Bought Sold

Latest quarter —

Net over range —

Buying quarters —

Insider Ownership Summary

Updated Oct 22, 2026

Over the past year, SMMT insiders bought $52.17 million of stock (3.96Mn shares) on the open market and sold none.

Counted by insider, open-market buying of SMMT stock in the past 12 months came from 2 insiders, with no insider selling.
Among Summit Therapeutics' insiders, Robert W. Duggan (Co-Chief Executive Officer) was the largest open-market buyer over the past 12 months, purchasing $51.45 million of stock (3.91Mn shares), most recently on June 12, 2026.
Apart from open-market trades, SMMT insiders received 100K shares in stock awards in the past 12 months.
Per Business Quant, SMMT insiders together hold 645.5Mn shares based on their latest Form 4 filings, up 0.02% from 645.4Mn shares at the end of Q2 2026 and up 8.41% from 595.42Mn shares at the end of Q3 2025.
Summit Therapeutics insiders hold 577.3Mn shares directly (89.43% of their total) and 68.2Mn shares (10.57%) indirectly, through entities such as trusts and partnerships.
Per Business Quant, 6 insiders of SMMT hold shares, counting officers, directors and 10% owners who have filed a Form 4 in the past two years.
Summit Therapeutics' three largest insider shareholders, based on their latest Form 4 filings, are Robert W. Duggan (Co-Chief Executive Officer, 599.79Mn shares), Yu Xia (Director, 32.06Mn shares) and Mahkam Zanganeh (Co-Chief Executive Officer, 10.23Mn shares).
The largest insider, Robert W. Duggan, holds 92.92% of SMMT's insider total.
Institutions held 17.14% of Summit Therapeutics' outstanding shares in their Q2 2026 13F filings, insiders about 81.39% based on their latest Form 4 filings, and other investors, including the public, the remaining 1.47%.
A total of 20 Form 4 filings with transactions in Summit Therapeutics stock were made over the past 12 months, by 10 insiders.
These insider figures for Summit Therapeutics are based on Form 4 filings through October 14, 2026.

Form 4 Holdings

Insiders Holding SMMT

Insiders 7

Shares held 1.21Bn

Of outstanding 152.49%

#	Insider	Position	Direct	Indirect	Total	Share of Insiders	Last Filed
1	Mahkam Zanganeh	Co Chief Executive Officer	0	599,708,353	599,708,353	49.6%	12 Jun, 2026
2	Robert W Duggan	Co Chief Executive Officer	573,883,879	0	573,883,879	47.5%	12 Jun, 2026
3	Yu Xia	Director	0	32,057,147	32,057,147	2.7%	23 Oct, 2025
4	Manmeet Singh Soni	Coo And Cfo	3,123,603	0	3,123,603	0.3%	04 Jun, 2026
5	Ankur Dhingra	Chief Financial Officer	0	354,958	354,958	0.0%	27 Mar, 2024
6	Bhaskar Anand	Chief Accounting Officer	261,047	0	261,047	0.0%	14 Oct, 2026
7	Jeff Huber	Director	0	44,052	44,052	0.0%	13 Sep, 2024

Each row is that insider’s most recently reported position, from Form 4 filings over the last 60 months — which is why this total does not tie to the quarterly series above, where a quarter counts only the insiders who filed in it. Shares held through a fund or institutional portfolio are counted on the institutional ownership page instead.

Form 4 Filings

185 Insider Transactions

Source SEC Form 4

Latest quarter Sep 2026

Date	Insider	Position	Transaction	Shares	Price	Value	Shares Held After	Ownership
08 Oct, 2026	Bhaskar Anand	Chief Accounting Officer	Acquired A	100,000	$0.00	$0	261,047	Direct
12 Jun, 2026	Robert W Duggan	Co Chief Executive Officer	Acquired P	3,810,000	$13.12	$49.99Mn	573,883,879	Direct
12 Jun, 2026	Mahkam Zanganeh	Co Chief Executive Officer	Acquired P	3,810,000	$13.12	$49.99Mn	573,883,879	Indirect
04 Jun, 2026	Manmeet Singh Soni	Coo And Cfo	Acquired P	25,000	$14.46	$361.50K	3,098,603	Direct
04 Jun, 2026	Robert W Duggan	Co Chief Executive Officer	Acquired P	100,000	$14.60	$1.46Mn	25,824,474	Indirect
04 Jun, 2026	Mahkam Zanganeh	Co Chief Executive Officer	Acquired P	100,000	$14.60	$1.46Mn	25,824,474	Indirect
04 Jun, 2026	Manmeet Singh Soni	Coo And Cfo	Acquired P	25,000	$14.43	$360.75K	3,123,603	Direct
08 Jan, 2026	Bhaskar Anand	Chief Accounting Officer	Acquired A	30,000	—	—	30,000	Direct
02 Jan, 2026	Alessandra Cesano	Director	Acquired A	35,000	—	—	35,000	Direct
02 Jan, 2026	Robert F. Booth	Director	Acquired A	35,000	—	—	35,000	Direct
02 Jan, 2026	Jeff Huber	Director	Acquired A	35,000	—	—	35,000	Direct
02 Jan, 2026	Mostafa Ronaghi	Director	Acquired A	35,000	—	—	35,000	Direct
02 Jan, 2026	Yu Xia	Director	Acquired A	35,000	—	—	35,000	Direct
02 Jan, 2026	Kenneth A Clark	Director	Acquired A	35,000	—	—	35,000	Direct
02 Jan, 2026	Mahkam Zanganeh	Co Chief Executive Officer	Acquired A	11,232	$8.76	$98.39K	11,232	Indirect
02 Jan, 2026	Robert W Duggan	Co Chief Executive Officer	Acquired A	11,232	$8.76	$98.39K	11,232	Direct
02 Jan, 2026	Kenneth A Clark	Director	Acquired A	17,796	$8.76	$155.89K	17,796	Direct
02 Jan, 2026	Robert F. Booth	Director	Acquired A	7,180	$8.76	$62.90K	7,180	Direct
02 Jan, 2026	Alessandra Cesano	Director	Acquired A	3,219	$8.76	$28.20K	3,219	Direct
02 Jan, 2026	Jeff Huber	Director	Acquired A	9,885	$8.76	$86.59K	9,885	Direct

Showing 1 to 20 of 185 transactions